PBP only supports 8-Bit PWM through either the PWM or HPWM commands, however, many PICs do support 10-bit Hardware PWM. If you decide to use HPWM you can set the most significant 8-bits through the HPWM command, and the least significant two bits can be set by accessing the PICs registers directly.

If you need to manipulate your 10-bits, then of course you need a WORD variable, and if you do that in BINARY, DECIMAL or HEX is up to you. But then if you need to set HPWM you'll have to extract the appropriate bits for the HPWM command.

You won't be able to have 10-bit PWM with the software PWM command.